On Mon, Feb 26, 2024 at 11:30 AM Kuldeep Singh <quic_kuldsing@xxxxxxxxxxx> wrote: > > > > > As we're not moving from the callers freely allocating what they need, > > > > to a fixed sized pool of 256kb. Please document why 256kb was choosen, > > > > so that we have something to fall back on when someone runs out of this > > > > space, or wonders "why not 128kb?". > > > > > > > > > > If you worry about these pools being taken out of the total memory and > > > prefer to have a way to avoid it, I was thinking about another > > > build-time mode for the allocator - one where there's no pool but it > > > just allocates chunks using dma_alloc_coherent() like before and pool > > > size is ignored. Does it sound good? > > > > > > > Or we could even have an argument for the initial size of the pool and > > then once it's exhausted, we'd add a new chunk (maybe twice the size?) > > and so on. > > Hi Bartosz, > > Thanks for shmbridge patch series. Few questions. > > 1. With current design of every client maintaining it's own pool, > For any target, we might end up occupying lot more space by > different clients than we actually need. > Technically there are only up to two, three in the future with scminvoke. > 2. Also, there's no option to configure pool size for each client at > runtime level and a fixed 256K value is chosen for qcom_scm/qseecom. You mean via a module parameter? > Pool size will be same for each target and thus making it less > scalabale if there's adjustment needed at target specific level. > Ex: For a low DDR memory target, pool size should scale down accordingly > as 256K will become a big ask but there's no way to choose specific pool > size for just one target. Do we really have any low-DDR platforms that would be affected by this change? Even for db401c the 256K is a tiny fraction of the total memory. > 2.1 One way to do configure custom pool size value is to add new > property in qcom_scm/qseecom or client DT node and then create > pool of size with this provided value. Though there are ways to > tackle this, but still clients specifying it's own pool size > will always fetch more CMA region than what is actually needed. > > Can you please share your ideas as well for upcoming version. > I will propose a new solution with several configuration options for pools. Including scaling the pool size as needed. I hope to send it this week. Bart > Regards > Kuldeep
